Interpretive Summary: Polycystic ovary syndrome (PCOS) is one of the most common hormonal disorders among women of reproductive age, affecting 5-10% of the population. In the absence of other hormone disorders, it is characterized by irregular menstruation, increased levels of male hormones and the presence of multiple cysts on the ovaries. It is associated with decreased insulin sensitivity and improvements in insulin sensitivity have been shown to lead to decreased signs and symptoms of the disease. We have shown previously that compounds found in cinnamon improve insulin sensitivity. Therefore, the purpose of the present study was to determine if components found in cinnamon would lead to increased insulin sensitivity in women with polycystic ovary syndrome. We demonstrated that consuming an extract of cinnamon for as little as 8 weeks led to very significant improvements in insulin function in women with polycystic ovary syndrome. This should be of direct benefit to the 5 to 10% of the population of child bearing age as well as the medical and scientific communities.